The Second Wrold Congress on Pain, sponsored by the International Association for the Study of Pain, will be held in Montreal, Canada on August 27 to September 1, 1978. Like the First World Congress which was held in Florence, Italy on September 5-8, 1975, the goals and objectives of the Congress are to bring together scientists, physicians, and other health professionals from various parts of the world and representing virtually every basic science and clinical discipline to report new information and reappraise current knowledge on pain mechanisms and various therapeutic modalities in current use. The scientific program of the Congress will include 5 plenary (single track) sessions, free communications, and other activities as described in the proposal. The plenary session and the free communications on Orofacial Pain will constitute approximately 25 percent of the scientific program of the Congress. In addition, a special satellite meeting on Orofacial Pain will be held prior to the Montreal Congress on August 25-26. 1978, in Toronto, Canada. In these two meetings it is planned to discuss virtually every aspect of orofacial pain. Based on the experiences of the First World Congress, it is anticipated that: (1) Over 1,000 biomedical scientists and health professionals, representing every basic science and clinical discipline from over half the countries in the world will attend the Second World Congress; (2) About 350-400 presentations will be made; (3) The Congress will enhance interaction, communication, and cross-fertilization among the participants of different disciplines; (4) It will greatly facilitate the rapid application of new knowledge to the diagnosis and treatment of acute and chronic pain, including that in the mouth and face. Moreover, the Congress should help define more clearly the needs and direction of future research efforts and provide opportunities for collaborative interdisciplinary study and treatment of orofacial pain. The ultimate goal is to help improve the care of patients with acute and chronic pain, which currently constitute a major national and world health and economic problem.